This proposal focuses on the technical aspects of islet isolation, which remains a substantial impediment to implementation of islet transplantation as a treatment for type 1 diabetes. Removing islets as soon as they are liberated from the pancreatic tissue mass during isolation and circumventing the need for density gradient purification is likely to result in substantially increased islet yields and potencies from donor pancreases. Instant separation of liberated islets would minimize exposure to proteolytic enzymes, reactive oxygen intermediates, and mechanical stress associated with centrifugation. The hypervascularity of islets compared with acinar tissue allows their preferential enrichment with magnetic beads, which in turn allows their immediate separation in a magnetic field before overdigestion, fragmentation, and loss of islet viability ensues. This proposal seeks to exploit these principles in the development of magnetic separation-based techniques for porcine and human islet processing for the purpose of maximizing the utilization of donor pancreases for islet transplantation. The University of Minnesota Diabetes Institute for Immunology and Transplantation, the Ohio State University Department of Chemical Engineering and the Cleveland Clinic Foundation Department of Biomedical Engineering, have established an interdisciplinary partnership to address the following Specific Aims (SA). SA#1: To develop a magnetic flow sorter for continuous and instant separation of islets liberated during the islet isolation process. SA#2: To compare the yield and potency of porcine islets isolated using conventional versus novel, magnetic separation-based processing methods. SA#3: To examine the feasibility of instant magnetic separation of human islets. The successful completion of the proposed studies will supercede current islet isolation and purification techniques. This advance is expected to 1), increase threefold the number of patients rendered insulin independent from the available cadaver donor pool and 2), to permit treatment of patients with islets isolated from a hemi-pancreas from living donors.